Photographic objective



"f -Kb?! KUUIVI H W 7W1! IT March 11, 1958 G. LANGE ,PHOTOGRAPHIC OBJECTIVE Filed July 16, 1954 United States Patent PHOTOGRAPHIC OBJECTIVE Giinther Lange, Konigsbronn, Germany, assignor to Carl Zeiss, Heldenheim (Brenz), Wurttemberg, Germany Application July 16, 1954, Serial No. 443,740

4 Claims. (CI. 88-57) The present invention concerns photographic objectives which possess an intercept length of more than 80% of the focal length and for this purpose contain a meniscusshaped dispersive front element. Such objectives are employed especially in the so-called monocular mirror reflex cameras, in which sufiicient room is to be provided between the objective and the film also for a folding mirror. Object of the invention is an objective of this kind, in which three further elements follow the mentioned dispersive front element, namely a biconvex collective element, a meniscus-shaped dispersive element, and a meniscus-shaped collective element, of which the two latter consist each of two cemented together lenses of opposite refractive power and turn the concave side to the diaphragm lying between them.

In order to attain for the mentioned intended use an adequate intercept length of the objective in accordance with the invention, the vertex distance between the surfaces bounding the first air space is suitably selected within the limits of 0.15-f and 1.5- f whereby f signifies the total focal length of the objective, whereby the distortion does notexceed the customary and tolerable degree.

For correction of the coma it is suitable to select the radius of the concave surface immediately following upon the diaphragm in amount at least 1.5 times as long, however not more than times as long as the radius of the concave surface lying immediately in front of the diaphragm. For the same reason one selects the radius of the surface of the last element turned towards the image smaller in amount than the radius of the surface of the collective element, following the front element, facing the dispersive front element.

Two execution Examples I and H of the objective in ac-' cordance with the invention are represented in the accompanying illustrations, and numerical values for these examples are specified in the following cited tables. In Figs. 1 and 2 and in the examples r signifies the radii d the thickness, and l the distances of the individual elements Besides the values for the refractive indices n and the Abbe numbers v as well as the refractive powers An/r of the individual surfaces are specified. The values are referred to a focal length f=1. Both examples possess a relative aperture of 1:5.6.

Patented Mar. 1 1 1 958 Example I [Intercept length-1.1181,]

Lenses Radll Thieknesses n4 0 An/r and Spaces Ti -+0. 722697 +0. 764248 Ll til-0. 01915 1. 55232 03. 5

li=0. 24761 ri=+0. 810884 +0. 768285 n 4P0. 06344 1. 62299 58. 1

1P0. 00633 +0. 249142 +2. 490347 Lrn.-.- tit-0.08250 1.62045 38.0

n- -0. 733171 -0. 140445 Lrv- (*0 01805 1. 72342 38. 0

11-0. 079215 -0. 722697 0. 832161 Lv dr==0. 01332 1. 60140 38. 3

fl -j-O. 256418 +0. 144842 Lvr-.- da=0.08909 1.63854 65.5

Example II [Intercept length-1.11354.)

Lenses Radfl Thicknesses m n An/r and Spaces n=+0. 738655 +0. 747737 Lr d1=0. 01929 1. 55232 63. 5

n= +0. 311483 1. 773195 lr=0. 25332 rs=+0. 805273 +0. 777227 Lu dz=0. 06459 1 62-588 35. 0

l2=0. 00587 rs -+0. 254648 +2. 428273 Lind|=0. 08153 1. 61835 36. 4

re- -0. 728103 0. 141683 Lrv. tit-0. 02181 1. 72151 29. 3

11:0. 08053 n=-0. 771251 -0. 788343 Lv 4P0. 01342 1. 60801 46. 2

n=+0. 243892 +0. 125178 Lvr--...- d4=0. 09143 1.63854 55.5

I claim;

1. A highly corrected photographic objective having an intercept length of more than percent of the total focal length comprising four lens components, the first being a dispersive meniscus-shaped component, the second a biconvex collective component, the third a meniscus-shaped dispersive component, and the fourth a meniscus-shaped collective component, the two latter said meniscus components each consisting of two cemented together lens elements of opposite refractive power and turnin their co cave surfaces towards the diaphragm located between "them, the vertex distance between t e two su aces bound- 3 3. Photographic objective according to the claim 1, the (I) each by at most $0.05 -f from the values to be taken refractive powers (An/r) each deviating at most by from the following numerical example: 0.2/f, and the lens thicknesses (d and the air distances (1) each at most :0.05 -f from the values to be taken from Thickness the following numerical example: Lem! g g "I 0. 738655- 0. 747737 Thickness, L f d1==0. 01020 1. 55232 03.5 I, Lenses Radtl and separem v Anlr a=+ 114=83J l :0 25332 f n+0.805273-f +0. 777227 1 Ln a I 41-0. 00450-1 1. 62588 35.0 +0 260346 .722007- 0.764248 n- 40403- L1 3 304758, cit-0.010104 1.5023: 03.5 254646, h= 005871 +2 428% 1 -024701-1 o'mmf ds=0.08153-j 1. 61836 30.4 0'141683 1 m5] Te-- d -0.00s44- 1.02200 53.1 LIV"-..- a =o.o21s1- 1. 72151 20.3 n--2.2ss4s-,r 0 +0.272s02 r1=-+o.22a710- 0 08053] 4.2252020 ,00633. s= 7 --0.771251- -0.7ssa43 Ll!!--.-- +0 mm! (it-0.08250 1.02045 sec v a I d==0013424 1.60801 40.: U n- 0. 7331714 -0. 140445]! o=+ 2 Lrv--... (It-0.01865! 1.7842 38.0 vI----- ds-o- 09143-1 1-63854 55.5

.402133 -3,305023/f f10=-0.375568 f +1. 700198/f 0 7220071 o 032101 1 r Lv l o 8 tit-0.013324 1.00140 38.3 +0 1 I being the focal length of the objective example Lv1..... J at -0.000001 1.638154 55.15 I "1 '10 befngthe "F m- -o.367451-! 37756/f d, d, being the thickness of, and

2 l l; the air separations between the individual lens elements L L f being the focal length of the objective example n being the refractive indices r r being the radii v being the Abbe numbers of the glass materials, and dz o being the thickness of and l e a e An/r being the refractive powers of the glass surfaces.

separations between the individual lens elements LI L References Cited in the file of this patent n being the refractive indices UNITED STATES PATENTS v being the Abbe numbers of the glass materials, and we being the eeeeeeve eeweee eeehe eleee eeeeeeee k333i? 1%;;::::::::::::::: 21. 3' iii? 4. Photographic objective according to the claim 1, the 2,341,385 Kingslake Feb. 8, 1944 refractive powers (An/r) each deviating at most by 2,622,480 Bertele Dec. 23, 1952 1:0.2/f and the lens thicknesses (d) and the air distances 2,649,022 Angenieux Aug. 18, 1953 

